1. Field of the Invention
This invention relates to a camera and more particularly to a video recording camera having image pick-up means and arranged to record a video signal on a record bearing medium through a recording head on the basis of an image pick-up signal obtained from the image pick-up means.
2. Description of the Prior Art
There have been proposed various video recording cameras of the above-stated kind. In this type of camera, if a predetermined amount of a video signal, such as one field or frame portion of a video signal, is arranged to be recorded in each recording track, while these tracks are formed in a concentric or annular manner on a magnetic disc or a drum or the like which is employed as a record bearing medium, that is, in a still video recording camera, the position of the recording head must be shifted relative to the record bearing medium unless the camera is provided with a multi-head arrangement.
Meanwhile, in order to ensure an adequate picture, a video recording camera must be provided with suitable control means for controlling the exposure of image pick-up means such as a shutter, a diaphragm, etc. Furthermore, where a view finder is arranged in the same manner as in a single-lens reflex camera, a movable mirror is necessary for selectively directing an image bearing light flux coming from a picture taking lens toward the image pick-up means and the view finder.
Furthermore, in light of the presently prevalent automatic focusing arrangement employed for cameras of the kind using silver halide film, there is also naturally a great demand for an automatic focusing arrangement for video recording cameras. Considering this, it is advantageous for a still video recording camera to have an automatic focusing device which includes such charging means as a spring, etc. and is arranged to perform a focusing operation by driving a picture taking lens with energy accumulated by the charging means. Such an arrangement not only serves to retain an important feature called "successive shootability" but is also advantageous in terms of reduction in cost.
Video recording cameras are thus required to have various operating means and devices as mentioned above. However, to provide each of these different operating devices separately with urging means and a drive source would result in a structural arrangement which is too large and complex for a camera which is reduced in size. Besides, such an arrangement also increases the probability of various malfunctions of the camera.
With respect to the functions of the video recording camera, there is a great demand for a successive shot function which permits repeated successive shooting as long as the camera trigger means is operated in addition to a normal single shot function which permits a shot to be made once every time the trigger means is operated. However, in view of the above-stated problem relative to the structural arrangement, the addition of the successive shot function has been difficult.
Meanwhile, the record bearing medium such as a magnetic disc or drum is housed within a container such as a cassette for easy handling. For the record bearing medium container, a record position indicating member, which is arranged to indicate a record position on the container, has been proposed for the purpose of preventing mishandling of the record bearing medium, such as double or duplicate recording, etc.
For the use of a record bearing medium which is housed in a container equipped with this indicating member, a video recording camera, of course, must be arranged to drive the indicating member in association with shifting the head mentioned in the foregoing. Furthermore, in that instance, the camera must be arranged to shift the position of the head on the record bearing medium until it comes to coincide with the record position indicated by the indicating member under a recording inhibited condition if the head position differs from the record position indicated. Then, such an arrangement further complicates the already complicated structural arrangement of the camera and thus further increases the probability of malfunctions.
Furthermore, in the event that the head position on the record bearing medium is thus continuously shifted until it comes to coincide with the position indicated by the indicating member of the container, it is obviously absurd to let power be continuously supplied to various means of the camera other than the head shifting means, such as the image pick-up means, recording means, exposure controlling means, record bearing medium driving means, etc., before the head position comes to coincide with the indicated record position. This is undesirable in terms of conserving power particularly for a hand-held camera or a portable type which has an internal power source of a limited capacity. Besides, with the power supply to the exposure control means kept on, if a camera is inadvertently triggered, an exposure would be wastefully carried out while no recording operation is performed. Such a wasteful exposure not only leads the operator to believe that an image has been recorded while no image has been recorded but also might result in failure of the image pick-up means to make an exposure during an actual picture taking operation since the shutter has already been released.